Nearby Protoclusters as Laboratories for Understanding Star Formation on Galactic Scales

Detailed studies of nearby cluster-forming molecular clouds can help us understand the physical processes by which most stars form in galaxies. I review recent advances made on this subject. Submillimeter observations of nearby protoclusters suggest that stars are generally built from finite, detached reservoirs of mass inside molecular cloud cores, and point to a cloud fragmentation origin for the IMF. Much progress in this field will come from future large submillimeter instruments such as Herschel and ALMA. This revised version was published online in September 2006 with corrections to the Cover Date.     

蓝田膨润土的发现及其物化性能研究

蓝田膨润土系笔者首次发现,本文初步研究了该膨润土的成分、属性、物化性能及其地质特征等。经研究认为,蓝田膨润土属钙镁基土,是比较少见的类型;除含大量蒙脱石外,还含一定数量的有益组分——凹凸棒石和高岭石;物化性能尚好;沉积成因,具有一定的规模和应用价值,建议应进一步进行普查找矿和应用开发研究。     

Scaling properties of Canadian flood flows

This study investigated the spatial scaling properties of Canadian flood flows, namely, annual maximum mean 1‐, 5‐ and 7‐day flows using both the product moments (PMs) and probability weighted moments (PWMs). Both approaches demonstrate that flood flows in climatic regions 1 (Pacific), 2 (South British Columbia mountains), 3 (Yukon and northern British Columbia), 6 (Northeastern forest), 7 (Great Lakes and St. Lawrence rivers), 8 (Atlantic), and 10 (Arctic tundra) exhibit simple scaling with scaling exponent θ/H close to 0·90, while flood flows in regions 4 (Prairie provinces), 5 (Northwestern forest), and 9 (Mackenzie) does not with scaling exponent θ/H close to 0·50. The plots of coefficient of variations of flood flows versus drainage area indicate that Cv remains almost constant in regions 1, 2, 3, 6, 7, 8, and 10, while it decreases as drainage area increases in regions 4, 5, and 9. These results demonstrate that the index flood method is applicable in climatic regions 1, 2, 3, 6, 7, 8, and 10, while it is not in climatic regions 4, 5, and 9. The physical backgroud of the simple scaling of flood flows in most Canadian climatic regions is that snowmelt or rain‐on‐snow runoff is a dominant flood‐generating mechanism across the country. Copyright © 2008 John Wiley & Sons, Ltd.     

埃尔米特插值函数在公路平面线形设计中的应用

三次样条函数在公路平面线形设计中有广泛的应用,但由于没有统一的函数表达式且计算量大,因而在应用上不便。埃尔米特插值函数的特点决定其能很好地逼近被插值函数,且计算过程简便。公路平面线形实例设计表明,三次埃尔米特插值函数用于公路平面线形设计中,能够满足路线设计规范(JTJ011-94)的要求,其设计结果与三次样条函数设计结果接近。本研究建立了公路平面线形设计的埃尔米特插值函数方法,可供公路平面线形设计工作参考。     

A new European testate amoebae transfer function for palaeohydrological reconstruction on ombrotrophic peatlands

Proxy climate data can be obtained from reconstructions of hydrological changes on ombrotrophic (rain‐fed) peatlands using biological indicators, such as testate amoebae. Reconstructions are based on transfer functions, relating modern assemblage composition to water table and moisture content, applied to fossil sequences. Existing transfer functions in Europe and elsewhere are limited geographically and there are often problems with missing or poor analogues. This paper presents a new palaeohydrological transfer function based on sampling raised mires from across Europe. Relationships between assemblages and hydrological variables are described using ordination analyses. Transfer functions are developed for depth to water table (n = 119) and moisture content (n = 132) with root mean squared errors (RMSEP) of 5.6 cm and 2.7% respectively. Both transfer functions have an r² of 0.71, based on ‘leave one out’ cross‐validation. Comparisons with an existing transfer function for Britain show that the European transfer function performs well in inferring measured water tables in Britain but that the British data cannot be used to infer water tables for other European sites with confidence. Several of the key missing and poor analogue taxa problems encountered in previous transfer functions are solved. The new transfer function will be an important tool in developing peat‐based palaeoclimatic reconstructions for European sites. Copyright © 2006 John Wiley & Sons, Ltd.     

一种深度图像拟合圆柱的优化方法

圆柱状构件广泛存在于古建筑仿真中,为了提高古建筑深度图像圆柱拟合的精度,针对古建筑仿真3维建模的特点,提出基于高斯图获取圆柱拟合参数初始值,然后利用圆柱距离函数参数化法进行非线性最小二乘拟合的圆柱拟合方法.实验证明,该方法不仅具有较高的精度,而且拟合结果稳定可靠.     

多面函数和移动法综合模型支持下的区域垂直形变场拟合

地壳垂直运动的研究中,多面函数法是一种传统并得到广泛应用的方法。本文通过首都圈和晋冀蒙两个地区的实例,对多面函数和移动法综合拟合模型与多面函数模型等几种模型进行了对比研究。结果表明,多面函数和移动法综合拟合模型在拟合精度上优于其他几种模型,拟合残差更稳定,具有一定的实际应用价值。